// 2.创建一个包含10个元素的RDD
// 将其中所有元素按空格切分成单词
// 并将所有单词变成小写形式（转换小写toLowerCase）
val data = List("Good morning","How are you ","Nice to meet you","Good afternoon","good evening","good night","see you tomorrow","bye bye","see you later")

val result =  data.flatMap(_.toLowerCase.split(" "))

println(result.mkString(","))